Keywords: carbon nanotubes, multi–walled CNTs, MWCNTs, E coli bacteria, biosensors, nanotechnology, DNA immobilisation, DNA sensor response, impact parameters, DNA sequence immobilisation, BSA agent blocking
Impact parameters investigation of DNA immobilisation process on DNA sensor response
This paper studies impact parameters of DNA sequence immobilisation on DNA sensor response. The parameters were examined including immobilisation time, carbon nanotubes concentration, DNA probe concentration and pH value. The DNA probe sequences were immobilised on surface of microelectrodes by using multi–walled carbon nanotubes (MWCNTs) as mediator. The hybridisation between DNA probe and DNA target was detected by changes in the conductance on the surface of sensors leading to the change in the output signal of the system. The experimental results showed that DNA sensor can well detect E. coli O157:H7 bacteria at optimal parameters including immobilisation time of 120 minute, MWCNTs of 1 mg, 20 µM DNA probe and pH7. Additionally, influence of BSA agent blocking was also studied. The result showed that DNA sensor response was decrease about 15% compared to that obtained in the absence of BSA blocking.